Lockstitch sewing machines



Dec. 5, 1967 J. R. IOANNILLI 3,356,046

LOCKSTITCH SEWING MACHINES Filed May 10, 1965 2 Sheets-Sheet 1 "Ill". f M

Joseph R loan/71W! ,By hzbfllforney Inventor:

Dec. 5, 1967 J. R. IOANNILLI LOCKSTITCH SEWING MACHINES 2 Sheets-Sheet 2 Filed May 10, 1965 United States Patent 3,356,046 7 LOCKSTITCH SEWING MACHINES Joseph R. Ioannilii, Beverly, Mass., assignor to United Shoe Machinery Corporation, Flemington, N.J., a corporation of New Jersey Filed May 10, 1965, Ser. No. 454,529 6 Claims. (Cl. 112-61) ABSTRACT OF THE DISCLOSURE A lockstitch shoe outsole sewing machine having a presser foot operated through connections including a floating lever which is locked in position by a pair of pinions in mesh with a sector connected to the floating lever and in which the locking action is provided by interlocking the pinions against relative rotation.

This invention relates generally to heavily constructed lo-ckstitch sewing machines such as are employed for sewing outsoles to shoes. More particularly the invention relates to an improved form of presser foot lock employed in such machines as a principal part of the connections for actuating and controlling the operation of the presser foot.

In a typical conventional outsole stitcher a presser foot, employed for clamping the welt and outsole on a work support, is raised and lowered once during each sewing cycle. The connections for raising and lowering the presser foot include a presser foot lock which performs two principal functions. The first of these is to assure uniformity of clamping pressure each time the presser foot grips the work even though the thickness of the work may vary considerably. The second function is to serve as a measure of work thickness during the formation of each stitch for the accurate measurement of needle thread for the formation of the next stitch.

Presser foot locks of varied designs have heretofore been employed with varying degrees of success. Shortcomings of prior locks include slippage under load, excessive time required to lock and unlock and high manufacturing costs. Slippage of a presser foot lock under load not only results in the work piece being inadequately camped for the formation of the stitch but also introduces unpredictable errors in the measurement of needle thread and consequent undetectable inaccuracies in the placement of thread within the work piece. Such inaccuracies often greatly reduce the holding power of the seam. The excess time required to lock and unlock prior devices is a major factor limiting the attainable sewing speed of outsole stitchers.

It is accordingly an object of the invention to improve the performance of presser foot locks by providing increased security against slippage.

Another object is to reduce the time required to open and close presser foot locks thereby to permit high speed operation of outsole stitchers.

Still another object is to reduce the cost and number of parts included in presser foot locks.

Yet another object is to facilitate the maintainance of presser foot locks in machines in the field.

The foregoing objects are realized in a presser foot lock according to a feature of the present invention in which a gear sector is locked against angular displacement in either direction by the engagement With its teeth of a pair of locking pinions. One of the pinions is mounted on a fixed axis and the other on a stud secured to a pivoted actuating arm. Both pinions mesh with the sector but their teeth are out of engagement with each other. One of the pinions is formed with an adjacent peripheral groove which receives a tapered tongue of the other.

3,35%,046 Patented Dec. 5, 1967 Since both pinions mesh with the sector, entry of the tongue of one pinion into the groove of the other prevents turning of the two pinions and locks the sector quickly in position.

An advantage of the lock already briefly described is that by rotating the pinions relative to each other and to the sector it is possible essentially to renew the lock mechanism without replacing parts.

The foregoing objects and features and numerous other advantages will be clarified from the following detailed description of an illustrative embodiment of the invention taken in connection with the accompanying drawings in which:

FIG. 1 is a view in perspective taken from a position slightly below and to the right rear of a shoe outsole sewing machine or stitcher including among presser foot actuating connections a presser foot lock according to the present invention;

FIG. 2 is a view in right side elevation and partially in section of the mechanism and lock illustrated in FIG. 1;

FIG. 3 is a view in front elevation showing the lock and connections of FIGS. 1 and 2; and

FIGS. 4 and 5 are detail views in right side elevation and plan respectively showing the engagement of a tongue on one pinion with a groove on another pinion forming a part of the present lock.

Turning now to the drawings, particularly FIGS. 1 and 2, the machine which provides the environment for the present invention includes a work support 10 which may be either fixed to a frame 12 or connected to mechanism for advancing it along the line of the scam in a feeding motion and for returning it to a position for the start of the next work advancing movement. The work piece shown as a shoe indicated generally at 14 and including a welt 16 and an outsole 18 is clamped on the work support 10 by a presser foot 20 which will be described in detail together with its actuating and control connections. While clamped by the presser foot 20 the edges of the welt 16 and outsole 18 are perforated by an awl 22 and the perforations are entered by a hook needle 24 which retracts carrying loops of thread through the work to be interlocked with a locking thread to form a seam.

The foregoing machine parts have been described briefly so that the invention which relates to the presser foot actuating connections will be better understood. The presser foot 20 is fixedly supported on the forward end of an actuating lever 26 shown pivoted on a stud 28. It will be appreciated that the pivotal support provided by the stud 28 is replaced by a ball mounting in machines in which the presser foot is moved in the direction of the seam. Such motion occurs for example in clamp feed machines in which the work piece is advanced by the work support 10 and the presser foot 20 clamping the work piece and moving together. At its rearward end the lever 26 is pivotally connected at 30 to a vertical link 32, the lower end of which is pivoted by a clevis pin 34 to the central portion of a generally horizontal floating lever 36. The forward end of the floating lever 36 is pivoted at 38 to a short vertical actuating link 40 for raising and lowering the presser foot and the rearward end of the floating lever is pivotally connected at 42 to a forwardly extending arm 44 formed integral with a gear sector 46. The level at which the pivot 42 is locked determines the distance from the work support at which the presser foot 20 begins its work clamping motion and the level of the pivot 42 also serves as the basis for the quantity of needle thread measured for the formation of the next stitch. The sector 46 is pinned on a transverse horizontal shaft 48 journalled in a pair of integral ears of the frame 12. The teeth of the sector 46 mesh with those of a pair of pinions 50 and 52 journalled on fixed and movable studs respectively. The pinion 50 is rotatable about a shoulder screw 54 threaded into the frame 12 while a similar screw 56 is threaded into a dependent arm of a lock actuating lever 58 rotatably to support the pinion 52. The lever 58 is free for rocking motion on the shaft 48 and its lower end is bifurcated to embrace an arm of a vertically disposed intermediate lock release lever 60 to which the lever 58 is connected by a pin 62. The lever 68 is fixed to a stud 63 journalled in an ear of the frame 12 and the pin 62 which is fixed to the lever 58 passes through an enlarged opening in the lever 60 to permit relative motion of the non-concentric levers 58 and 60. The lock release lever 68 also includes an up wardly extending arm 64 through which it receives a lock releasing motion from mechanism to be described. The lock is kept engaged between releasing motions by a tension spring 66 stretched between the lower end of the arm 60 and a fixed anchor point on the frame.

The sring 66 urges the pinion 52 toward the pinion 58 and, while the two pinions are so related, the sector 46 and the pivot 42 are firmly locked in position. This is accomplished by preventing rotation of the pinions 50 and 52 by means of a peripheral groove 68 which is formed concentrically with the pinion 50, and is entered by a peripheral tapered tongue 70 machined concentrically with the pinion 52. Under the urging of the spring 66 the tongue 70 is wedged into groove 68 thereby preventing both the pinions 50 and 52 and the sector 46 from turning about their respective axes. The lock is released to permit the level of the pivot 42 to be adjusted freely by pulling the pinion 52 away from the pinion 50 thus disengaging the tongue 70 from the groove 68 and allowing both pinions to rotate freely. To release the lock, the lever 60 is rocked slightly in a clockwise direction either at the proper time during each sewing cycle or at the end of a seam to permit the removal of the work piece. A tie rod 72 is moved rearwardly to the right as seen in FIG. 1, to release the lock at the end of a seam. Motion is imparted to the rod 72 by conventional connections to the driving and stopping mechanism.

The relative timing in the locking and unlocking of a presser foot lock and in the raising and lowering of the presser foot of a modern high speed stitcher during each sewing cycle will be more fully appreciated from the disclosure of application for United States Letters Patent No. 422,853, filed Dec. 21, 1964 in my name and those -of Mieth Maeser and K. H. Rouschke. For releasing the lock once during each sewing cycle there is provided a mechanism including a lever 74 hearing a follower roll 76 at its upper end and carrying a set screw 78- at its lower end. The lever 74 is pivoted on a fixed shaft 80 which is fixedly supported in the frame 12 and the lever is actuated through its releasing motion by the engagement of the follower roll 76 with a cam track 82 cut in a cam body 84. The body 84 is keyed to a shaft 86 which may be the single shaft or one of a pair upon which cams and other drives are mounted for actuating not only the presser foot but also the stitch forming and thread controlling instrumentalities of the machine. Whether the shaft 86 is the only shaft as illustrated or one of a plurality it is journalled in the frame 12 and rotated one revolution during the formation of each stitch, the shape of the track 82 causing the lever 74 to be oscillated once during each sewing cycle. As the lever pivots in a counterclockwise direction as seen in FIG. 1 the screw 78 engages ,the arm 64 of the intermediate release lever and withdraws the tongue 7 from the groove 68 against the force of the spring 66. As the tongue and groove become separated both pinions 50 and 52 and the sector 46 are freely rotatable.

The release of the sector 46 during each sewing cycle occurs while the presser foot 20 is in raised position and the sector is locked as the presser foot is being lowered toward the work support 10 by means which will be described. The lowering of the presser foot causes the floating lever 36 to be positioned so that the level of the pivot 42 provides a measurement of the thickness of the work between the work support and presser foot. The position of the pivot 42 and the corresponding angular orientation of the shaft 48 is employed for regulating the amount of needle thread measured for the formation of the next stitch in accordance with the thickness of the work.

For urging the presser foot toward the work support while the sector 46 is free to move there is utilized in the present machine a compensated spring system such as that disclosed in application Ser. No. 361,961, filed jointly Apr. 23, 1964 in my name and that of Roger E. Lemay. The spring system comprises a torsion spring 90 having one end coupled to an adjusting rod 1 and its other end terminating in a hook 92. A force compensating cam 94 is fixedly mounted on the shaft 48 and coupled by a steel tape 96 to the hook 92 so that whenever the sector 46 is free to rotate the pivot 42 is urged in a clockwise direction as seen in FIGS. 1 and 2 about the axis of the shaft 48. This spring force is translated whenever the sector 46 is released, through the motion of the floating lever 36, the link 32 and presser foot lever 26 into a lowering of the presser foot 20 into contact with the work piece on the work support 10.

After the presser foot 20 has engaged the work piece, the sector 46 is locked and the pivot 38 on the floating lever 36 is raised to impart a further predictable clamping motion to the presser foot in order to clamp the work piece uniformly against the work support 10 regardless of work piece thickness. For raising the pivot 38 to lower the presser foot and for depressing the pivot to raise the presser foot, the link 40 is bifurcated at its upper end to receive a forwardly extending arm of an actuating lever 98 pivotally supported on the shaft 88. The arm is formed with an arcuate slot 100 for providing an adjustable pivotal connection by means of a shoulder screw 102 between the link 40 and the lever 98. For oscillat'mg the lever 98 there is mounted on its other arm a follower roll 104 which engages a cam track 106 in the body 84. The effect of the motion imparted to the lever 98 by the shape of the track 106 may be modified by the positioning of the shoulder screw 102 in the slot 100. Thus when the screw 102 is positioned closest to the shaft 80 a minimum motion is imparted to the pivot 38 and consequently to the presser foot 20. As the distance between the shaft 80 and the shoulder screw 102 is increased the motion of the presser foot is proportionally increased. The release of the sector 46 by disengaging the tongue 70 from the groove 68 is accomplished in timed relationship with the motion of the presser foot as determined by the shape of the tracks 82 and 106. The lock is released by the engagement of the set screw 78 with the upstanding arm 64. The exact timing of presser foot lock release may be varied somewhat by the adjustment of the screw 78 which is locked in predetermined position in the depending arm of the lever 74 by a lock nut 108. In addition to the release of the lock once during each sewing cycle, it is also released at the end of a seam to facilitate the removal of the work piece. For this purpose the tie rod 72 is connected to an arm 110 inegral with the lever 58 so that the connections for releasing the lock at the end of the seam are independent of the mechanism which controls the engagement and release of the lock during the formation of stitches.

The thread measuring function of the angular position of the sector 46 will be best understood by referring to the above-identified application Ser. No. 422,853. There is disclosed in that application a thread measuring mechanism in which the amount of thread measured for each stitch is controlled by the angular orientation of a sleeve 112 in which a shaft 114 is journalled. The same reference characters 112 and 114 designate the sleeve and shaft respectively in the present application. From this prior application, it will be seen that a greater quantity of thread is measured as the sleeve 112 is moved in a clockwise direction as seen in FIGS. 1 and 2. In the present machine thread measuring connections interposed between the floating lever 36 and the shaft 114 are somewhat different from those of my prior application. These connections include an arcuate slotted arm 116 pinned to the shaft 48. The slot indicated at 118 is penetrated by a shoulder screw to provide an adjustable connection through which the angular position of the sector 46 is transmitted to the sleeve 112. A shouldered and threaded stud 120 mounted on the forward end of a link 122 and retained in place by a check nut 124 provides a pivotal connection between the arm 116 and the link which at its rearward end is also pivoted at 126 to an arm 128 secured to the sleeve 112. By clamping the stud 120 at the upper end of the slot 118 nearest the shaft 114 the eifect of changes in the angular position of the sector 42 on thread measurement is minimized. As the position of the stud 120 is lowered in the slot 118 this effect is increased. The purpose of the adjustable connection thus provided is to suit the quantity of thread measured in accordance with the thread receiving characteristics of various sole materials which may range from relatively soft yielding rubber and plastics to relatively incompressible leathers and other sole materials.

Having thus disclosed my invention what I claim as new and desire to secure by Letters Patent of the United States is:

1. A lockstitch shoe outsole sewing machine comprising a presser foot, means for actuating the presser foot during each sewing cycle including a floating lever, a gear sector connected to the floating lever and mounted about an axis for angular movement in accordance with the position of the floating lever, a pair of gear pinions in toothed engagement with the sector and releasable means for urging the pinions into interlocking relationship with one another, thereby preventing relative rotation of the pinions to lock the sector against angular displacement about its axis.

2. A lockstitch shoe outsole sewing machine comprising a presser foot, means for actuating the presser foot during each sewing cycle including a floating lever, a gear sector connected to the floating lever and mounted about an axis for angular movement in accordance with the position of the floating lever, a first gear pinion in toothed engagement with the sector and rotatable about a stationary axis, an arm pivoted about the axis of the sector, a second pinion rotatable about an axis on the arm and in toothed engagement with the sector and releasable means for preventing relative rotation of the pinions to lock the sector against angular displacement about its axis.

3. A lockstitch shoe outsole sewing machine comprising a presser foot, means for actuating the presser foot during each sewing cycle including a floating lever, a gear sector connected to the floating lever and mounted about an axis for angular movement in accordance with the position of the floating lever, 21 pair of gear pinions in toothed engagement with the sector, one of the pinions being formed with a peripheral angular groove concentric with its pitch circle, a tapered tongue formed concentric with the pitch circle of the other pinion, releasable means for urging one of the pinions toward the other for engaging the tongue in the groove to prevent rotation of the pinions and to lock the sector against angular displacement about its axis.

4. A lockstitch shoe outsole sewing machine comprising a presser foot, means for actuating the presser foot during each sewing cycle including a floating lever, a gear sector connected to the floating lever and mounted about an axis for angular movement in accordance with the position of the floating lever, a first gear pinion in toothed engagement with the sector and rotatable about a stationary axis, an arm pivoted about the axis of the sector, a second pinion rotatable about a movable axis on the arm and in toothed engagement with the sector, resilient means for urging the arm toward a position in which both pinions and the sector are locked against rotation and means for moving the second pinion away from the first once during each sewing cycle.

5. A lockstitch shoe outsole sewing machine comprising a presser foot, means for actuating the presser foot during each sewing cycle including a floating lever, a gear sector connected to the floating lever and mounted about an axis for angular movement in accordance with the position of the floating lever, a pair of gear pinions in toothed engagement with the sector and mounted for movement toward and away from each other, one of the pinions being formed with a peripheral angular groove concentric with its pitch circle, a tapered tongue formed concentric with the pitch circle of the other pinion, resiiient means for urging the pinions toward each other to lock the pinions and the sector against rotation and means for moving the pinions apart once during each sewing cycle.

6. A lockstitch shoe outsole sewing machine comprising a presser foot, means for actuating the presser foot during each sewing cycle including a floating lever, a gear sector connected to the floating lever and mounted about an axis for angular movement in accordance with the position of the floating lever, a first gear pinion in toothed engagement with the sector and rotatable about a stationary axis, an arm pivoted about the axis of the sector, a second pinion rotatably mounted on the arm and in toothed engagement with the sector, interlocking means including a tapered peripheral tongue concentric with one of the pinions and a peripheral angular groove concentric with the other pinion and having a cross section complementary to the tongue and resilient means urging the tongue into the groove for preventing relative rotation of the pinions to lock the sector against angular displacement about its axis.

References Cited UNITED STATES PATENTS 1,194,491 8/1916 Erickson 112-61 2,337,252 12/ 1943 Krag 11261 3,272,162 9/1966 Ioannilli 112-61 PATRICK D. LAWSON, Primary Examiner. 

1. A LOCKSTITCH SHOE OUTSOLE SEWING MACHINE COMPRISING A PRESSER FOOT, MEANS FOR ACTUATING THE PRESSER FOOT DURING EACH SEWING CYCLE INCLUDING A FLOATING LEVER, A GEAR SECTOR CONNECTED TO THE FLOATING LEVER AND MOUNTED ABOUT AN AXIS FOR ANGULAR MOVEMENT IN ACCORDANCE WITH THE POSITION OF THE FLOATING LEVER, A PAIR OF GEAR PINIONS IN TOOTHED ENGAGEMENT WITH THE SECTOR AND RELEASABLE MEANS FOR URGING THE PINIONS INTO INTERLOCKING RELATIONSHIP WITH ONE ANOTHER, THEREBY PREVENTING RELATIVE ROTATION OF THE PINIONS TO LOCK THE SECTOR AGAINST ANGULAR DISPLACEMENT ABOUT ITS AXIS. 